Set the grahpicssystem to "raster" in the code after the reported performance

benefits.  This can be overriden on the commandline with -graphicssystem

ground/openpilotgcs/src/app/main.cpp

@@ -239,6 +239,8 @@ int main(int argc, char **argv)
     setrlimit(RLIMIT_NOFILE, &rl);
 #endif
 
+    QApplication::setGraphicsSystem("raster");
+
     SharedTools::QtSingleApplication app((QLatin1String(appNameC)), argc, argv);
 
     QString locale = QLocale::system().name();